Reptile Heating Calculator
Calculate the right heating wattage, basking temperature, and gradient for your reptile enclosure based on species and tank size.
Reptile Heating is critical because reptiles are ectotherms — they regulate body temperature using external heat sources. Incorrect temperatures lead to poor digestion, weakened immune systems, and metabolic bone disease.
Temperature Gradient: Every reptile enclosure needs a warm side (basking zone) and a cool side. This gradient allows the animal to thermoregulate by moving between zones.
Species Temperature Requirements:
| Species | Basking °F (°C) | Warm Side °F (°C) | Cool Side °F (°C) | Night °F (°C) |
|---|---|---|---|---|
| Bearded Dragon | 100–110 (38–43) | 85–90 (29–32) | 75–80 (24–27) | 65–75 (18–24) |
| Leopard Gecko | 88–92 (31–33) | 80–85 (27–29) | 72–77 (22–25) | 65–72 (18–22) |
| Ball Python | 88–92 (31–33) | 80–85 (27–29) | 75–80 (24–27) | 72–78 (22–26) |
| Corn Snake | 85–88 (29–31) | 78–82 (26–28) | 70–75 (21–24) | 65–72 (18–22) |
| Blue-Tongued Skink | 95–100 (35–38) | 80–85 (27–29) | 70–75 (21–24) | 65–70 (18–21) |
| Crested Gecko | No basking | 72–78 (22–26) | 68–72 (20–22) | 65–72 (18–22) |
| Chameleon | 85–90 (29–32) | 75–80 (24–27) | 68–72 (20–22) | 60–68 (16–20) |
Wattage Estimation: The wattage needed depends on the temperature difference between room temperature and the basking target, plus the enclosure size.
Rule of Thumb:
Wattage ≈ Enclosure Volume (gallons) × Temperature Difference (°F) × 0.1
For metric: Wattage ≈ Volume (liters) × Temp Diff (°C) × 0.47
This is approximate — the actual wattage depends on insulation, lamp height, and room conditions.
Common Heat Sources:
| Type | Wattage Range | Best For |
|---|---|---|
| Basking bulb | 50–150W | Basking spot, daytime heat + light |
| Ceramic heat emitter | 60–150W | 24-hour heat without light |
| Under-tank heater | 8–24W | Belly heat for ground-dwellers |
| Radiant heat panel | 40–120W | Large enclosures, arboreal species |
Practical Example: A 40-gallon (150 L) bearded dragon enclosure. Room temperature: 72°F (22°C). Target basking: 105°F (40°C). Temperature difference: 33°F (18°C). Estimated wattage: 40 × 33 × 0.1 = 132W. A 100W basking bulb + supplemental ceramic heat emitter would be appropriate.
Tips:
- Always use a thermostat to prevent overheating.
- Measure temperatures with a digital thermometer or infrared temp gun, not stick-on thermometers.
- Place the thermometer probe at the basking surface, not in the air.
- Night temperatures should drop, but not below the species minimum.
- Never use hot rocks — they cause thermal burns.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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